| 摘要 |
PURPOSE:To prevent the discoloration of an image by making a toner in the 1st developer show polarity contrary to the polarity of a toner in the 2nd developer when it is electrostatically charged in the 2nd developer so as to inhibit the toner in the 1st developer from sticking to an image developed with the 2nd developer. CONSTITUTION:When the 1st and the 2nd developers are separately stirred at developing parts 4, 7, a toner T1 in the 1st developer and a toner T2 in the 2nd developer are electrostatically charged to show the same positive polarity. Part of the toner T1 developing the 1st latent image is scraped away and enters the 2nd developer, but when the toner T1 is stirred in the 2nd developer, it shows negative polarity contrary to the positive polarity of the toner T2 and does not stick to the 2nd latent image. Accordingly, the 1st and the 2nd latent images S1, S2 are developed with the toners, T1, T2, respectively, and the image S2 is not developed with the toner T1, so the resulting image is not discolored. |
